Many data transmission methods which are important in practice have no capability to deactivate a transmission mode in order to switch a transmitting/receiving device to an energy saving mode, in an advantageous manner, and on the other hand to, provide an effective and rapid hot start.
xDSL technologies relate to various types of use/carrier methods for lines to which packet-oriented or row-oriented protocols can be applied. By way of example, DSL (digital subscriber line=digital interface line), ADSL (asymmetrical DSL), SDSL (single line DSL), HDSL (high data rate DSL) and a combination of the last two transmission methods, S(H)DSL are used on conventional telephone lines from an exchange-end transmitting/receiving device to a subscriber-end transmitting/receiving device.
Until now, transmission methods such as these have had the disadvantage that no hot start capability is provided.
Methods according to the prior art provide hot start capabilities for ISDN (integrated services digital network), as described by way of example, at the exchange end, for a data transmission rate of 144 kbps in “ETSI TS 102 080, Integrated Services Digital Network (ISDN) basic rate access, Third Edition, November 1998” and the Publication “ANSI TI,601-1988, Integrated Services Digital Network (ISDN), ANSI, September 1988”.
Until now, particularly for S(H)DSL transmission methods, there has been no capability to carry out a hot start after deactivation of a data transmission path, as described, by way of example, in “ITU-T G.991.2, Single-pair high-speed digital subscriber line (SHDSL) transceivers”, “ETSI TS 101 524 Symmetric single pair high bit rate digital subscriber line (SDSL)”.
One disadvantage of the “Deactivation Text Proposal” in the literature reference “Adtran, Deactivation Text Proposal, ETSI-Meeting, TM6, Helsinki, May 2000, 002t35a0” is that it is impossible to cancel any deactivation, and the deactivation process takes place only after a fixed time has elapsed.
Conventional methods and apparatuses for transmission of data streams which are to be transmitted thus require lengthy cold starts, that is to say activation and adaptation of exchange-end transceivers and subscriber-end transceivers to line characteristics of a data transmission path.
A matching process such as this has the disadvantage that it typically requires a time period of 30 seconds or more. If hot starts were possible, a deactivated line or a deactivated data transmission path could be activated in a fraction of the abovementioned time period (in a time period of approximately 500 milliseconds), based on the knowledge of the line characteristics, which would result in a considerable advantage for the setting up of a data transmission line.
Methods and apparatuses according to the prior art disadvantageously consume power, in particular in the exchange-end transmitting/receiving devices and in the subscriber-end transmitting/receiving devices, even when the at least one data stream which is to be transmitted does not contain any payload data.